import java.util.Scanner;

public class zhengze {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String str = scanner.next();
        String emailMatcher="[a-zA-Z0-9]+@[a-zA-Z0-9]+\\.[a-zA-Z0-9]+";

        if(str.matches(emailMatcher)){
            System.out.println("邮箱格式合法");
        }else{
            System.out.println("邮箱格式不合法");
        }
    }

}
